As per another thread, I have yet to change out the 7 pin cable.Prior to doing so, I decided to confirm whether the old cable is still usable.I hooked up the 7 pin to the truck (which recognized the trailer), and ran through the lights/turn signal/brake lights process (can't recall what that process is called) and all lights worked and message indicated no issues.However, the manual brake controller does not activate the trailer brakes, nor does applying the truck brake pedal.So, a couple questions:- Don't really understand the a/m check process. Does it only show the wiring to the various lights is working? In other words, this does not test the full brake circuit?- if that is correct, no brakes then suggests there is an issue somewhere after the 7 pin cable?- And if there is an issue at one of the brakes (ie loose wire), will that affect all brakes?Thanks in advance,Marv

How do you know the controller isn’t activating the brakes? Did you use a compass or listen for the hum at the wheels?

sitting still, the Brake pedal will NOT activate the brakes. But, the manual lever will. Start the truck, use the manual brake lever/button and attempt to pull forward. After less than a foot the brakes on trailer should lock up and stop you. Trailer brakes operate on dc voltage. 12 volts to the brakes is FULL lock up brakes. 1 volt thru 11 volts will activate in increments. Doug

Thanks for the replies.And I should have been more clear. I actually hooked up the trailer to the truck and pulled it down a few streets, fully applying the brake controller, then applying the foot brake. Both a few times. Absolutely no resistance at all, either method.Marv

To see if the trailer side is good, jump 12v to trailer side pin for the brakes. Should lock them up tight. Your truck sounds fairly new. Is there a readout for trailer brake gain?

marpel wrote:Thanks for the replies.And I should have been more clear. I actually hooked up the trailer to the truck and pulled it down a few streets, fully applying the brake controller, then applying the foot brake. Both a few times. Absolutely no resistance at all, either method.MarvYou have two things to check: Electrical power reaching the magnets and shoes adjusted properly. To check power, you can hold a compass near the drum just under the center of the wheel and look for deflection when the brakes are applied.Adjusting the brakes is a little more work and requires jacking up the trailer. This is recommended every 3,000 miles, so it’s possible for the brakes to fairly quickly reach the point they don’t do any braking without regular maintenance.If neither of those steps help, it’s not unlikely the brakes are contaminated from overgreasing at the factory or later via using a grease zerk on the axle. Determining if this is the issue requires hub disassembly, but if you have any doubts about the brake or bearing condition it’s a good idea to open it up and look.

Trailer Brakes | Good Sam Community

prichardson
Explorer
May 29, 2022
You need to confirm that you are getting brake voltage at the truck side of the 7 pin connector. If not the problem is in the truck not the trailer.
jkwilson
Explorer III
May 29, 2022
marpel wrote:
Thanks for the replies.

And I should have been more clear. I actually hooked up the trailer to the truck and pulled it down a few streets, fully applying the brake controller, then applying the foot brake. Both a few times. Absolutely no resistance at all, either method.

Marv

You have two things to check: Electrical power reaching the magnets and shoes adjusted properly.

To check power, you can hold a compass near the drum just under the center of the wheel and look for deflection when the brakes are applied.

Adjusting the brakes is a little more work and requires jacking up the trailer. This is recommended every 3,000 miles, so it’s possible for the brakes to fairly quickly reach the point they don’t do any braking without regular maintenance.

If neither of those steps help, it’s not unlikely the brakes are contaminated from overgreasing at the factory or later via using a grease zerk on the axle. Determining if this is the issue requires hub disassembly, but if you have any doubts about the brake or bearing condition it’s a good idea to open it up and look.
Grit_dog
Navigator
May 29, 2022
To see if the trailer side is good, jump 12v to trailer side pin for the brakes. Should lock them up tight.
Your truck sounds fairly new. Is there a readout for trailer brake gain?
marpel
Explorer
May 29, 2022
Thanks for the replies.

And I should have been more clear. I actually hooked up the trailer to the truck and pulled it down a few streets, fully applying the brake controller, then applying the foot brake. Both a few times. Absolutely no resistance at all, either method.

Marv
dougrainer
Nomad
May 29, 2022
sitting still, the Brake pedal will NOT activate the brakes. But, the manual lever will. Start the truck, use the manual brake lever/button and attempt to pull forward. After less than a foot the brakes on trailer should lock up and stop you. Trailer brakes operate on dc voltage. 12 volts to the brakes is FULL lock up brakes. 1 volt thru 11 volts will activate in increments. Doug
jkwilson
Explorer III
May 29, 2022
How do you know the controller isn’t activating the brakes? Did you use a compass or listen for the hum at the wheels?

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